Mac OS X calculator

Discussion in 'Mac Apps and Mac App Store' started by samanthas, Feb 15, 2006.

  1. samanthas macrumors regular

    Joined:
    Sep 21, 2005
    Location:
    Portland, OR
    #1
    Ok so, how do you do a percentage? I can't believe the calculator doesn't have a percentage!

    And also, if there another calculator that I can download somewhere? Widget or not.
     
  2. Wes macrumors 68020

    Wes

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    Jun 22, 2001
    Location:
    London
    #2
    Open the program, go to view, select scientific.
     
  3. Thomas Harte macrumors 6502

    Joined:
    Nov 30, 2005
    #3
    In the menubar, select View->Scientific to enable a wider version of the calculation, with a percentage button. But I've never really understood the point of it - doesn't it just divide by 100?
     
  4. Wes macrumors 68020

    Wes

    Joined:
    Jun 22, 2001
    Location:
    London
    #4
    Yeah, quite a pointless button, probably why they left it off.
     
  5. Doctor Q Administrator

    Doctor Q

    Staff Member

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    Sep 19, 2002
    Location:
    Los Angeles
    #5
    I find it annoying to have to use menu choices with a calculator. Luckily, Command-1 and Command-2 (and Command-3 for us programmers) are there to save the day.
     
  6. mrichmon macrumors 6502a

    Joined:
    Jun 17, 2003
    #6
    Err...

    How difficult is it to multiply by 0.60 to get 60%?
    Or multiply by 0.0125 to get 1.25%?
    Or multiply by 0.99 to get 99%?

    Are you seeing a pattern here? Yes, it is the same pattern that you learnt in school. :)
     
  7. MacRumoron macrumors 6502

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    Sep 6, 2005
    #7
  8. Doctor Q Administrator

    Doctor Q

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    #8
    Some calculators are smarter about percentages, letting you add 7% tax to the price of a $9.95 item by pressing
    which would make it a little more convenience than having to press
    Even more so if you want to take 4.5% off a price, where
    would be easier than
    But Apple's calculator doesn't do % shortcuts like those.

    Oddly, if you press 7 % you get 0.07000000000000001 but if you press 7 % = you get 0.07.
     
  9. Edot macrumors 6502

    Joined:
    Jan 29, 2002
    Location:
    NJ
    #9

    Yeah whoever coded the Calculator app needs some serious help. It was full of errors a while ago, and they still haven't got their float conversions right.
     
  10. samanthas thread starter macrumors regular

    Joined:
    Sep 21, 2005
    Location:
    Portland, OR
    #10
    You don't have to be so rude. Geez. I just happen to like having a percentage button.

    Thanks for those who helped me though.
     
  11. Mitthrawnuruodo Moderator emeritus

    Mitthrawnuruodo

    Joined:
    Mar 10, 2004
    Location:
    Bergen, Norway
    #11
    Edit: Forget my first respond... I'm stupid... :eek: ;)

    But even weirder... if you press 7 % 7 (or substitute the second 7 with any number) you get 0.0700000000000000
     
  12. jblock macrumors regular

    Joined:
    Jan 4, 2006
    #12
    Yes, I keep waiting for the calculator to be updated to do simple percentage calculations. Is this even on Apple's radar?
     
  13. stridey macrumors 65816

    stridey

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    Jan 21, 2005
    Location:
    Massachusetts, Connecticut
    #13
    Just use Google. It'll calculate any mathematical expression. :)
     
  14. Doctor Q Administrator

    Doctor Q

    Staff Member

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    Sep 19, 2002
    Location:
    Los Angeles
    #14
    Google doesn't handle +% (sales tax) or -% (discount) either.

    Instead of
    Code:
    9.95 + 7% = 10.6465
    it computes it as
    Code:
    9.95 + 7% = 10.02
    It's interesting that such a simple expression can have two different meanings.

    Google and Calculator.app consider % in this case to mean "divided by 100", although Google also knows that 7% of 9.95 = 0.6965.

    In the sales tax case, we humans consider % to be a verb taking an object, x percent of y, with a default object of the previously mentioned noun, so 9.95 + 7% means 9.95 + (7% of 9.95).
     
  15. mrichmon macrumors 6502a

    Joined:
    Jun 17, 2003
    #15
    The issue is that + 7% is not a valid mathematical expression. Or even a valid logical expression since there is no mention of what the 7% refers to. Is it the immeadiately preceeding value, the following value, or some other value?

    For example, what does this mean?: 9.95 + 7% + 20
     
  16. Doctor Q Administrator

    Doctor Q

    Staff Member

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    #16
    I think we are agreeing. It could be interpreted to mean either
    Code:
    9.95 + (7% of 9.95) + 20
    or
    Code:
    9.95 + (7 / 100) + 20
    Thinking of it another way, % should have two operands. When people omit the second operand, the "default" could be either the number mentioned before it, or it could be the number 1, since (7 % of 1) is (7 / 100).

    Given the ambiguity, some calculators handle it one way and others another way.
     
  17. Mr. Mister macrumors 6502

    Joined:
    Feb 15, 2006
    #17
    I forget, does Mac OS X install with the calc app having all the other extensions, like Hex and Binary, or do you still have to move them around inside the Calculator.app package?
     
  18. mrichmon macrumors 6502a

    Joined:
    Jun 17, 2003
    #18
    Yes, or it could mean 9.95 + (0.07 * 20), or 9.95 + (0.07 * arbitrary value) + 20.

    Ultimately, % is not strictly an operator. Rather, it is a symbol denoting a concept. Since it is not a mathematical operator, various calculator implementations (hardware and software) implement it as a convenience function but do so in different ways.

    I would argue that due to the ambiguity and thus the potential for errors in use, it is far better to ignore this button and handle percentage calculations manually as a multiplication. But then this is also because I believe that people should understand what is going on.

    But yes, I think we are agreeing.
     
  19. Doctor Q Administrator

    Doctor Q

    Staff Member

    Joined:
    Sep 19, 2002
    Location:
    Los Angeles
    #19
    Press Command-3 in Calculator.app.
     

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